In metalworking operations where a workpiece is machined, equipment of some type is necessary to hold the workpiece in position in a machine tool so the machining process can be successfully carried out. This type of equipment is known as “workholding” equipment.
It is well known in machining processes for a workpiece to be transported to and/or from the workholding equipment via transfer device. In one known embodiment, workpieces are transferred between a cutter spindle and an auxiliary spindle where another process (e.g. chamfering) may be carried out. One manner of transferring a workpiece between spindles is via a rotary transfer arm. The rotary arm usually comprises a pair of workholding devices (e.g. chucks) that grasp a workpiece during the transfer. Each chuck usually includes a gripper device comprising a plurality (e.g. two or three) of jaws. The form of the grippers is usually one which compliments the form of that portion of workpiece to be gripped. In bevel gear manufacture, for example, different jaw forms or shapes would be required depending upon whether the part being gripped is a bevel pinion or a bevel ring gear as can be appreciated by the artisan.
On a machine having a transfer mechanism, a change in the type of workpiece being processed usually requires a change in the type and/or shape of the jaws of the chucks on the transfer mechanisms. Generally, this involves removing of a plurality of bolts to release each jaw from its associated chuck body and replacing the bolts when securing the replacement jaw to the chuck body. Such a task is time consuming, requires one or more tools and presents the possibility of thread damage to the bolts and/or chuck body.
It is an object of the present invention to provide a gripping apparatus whereby jaws are quickly and easily exchanged without the need for tools.